All in one Gusset and Base for Crossbody handle

Hi everyone , just puzzled on my bag design . I have kangaroo leather that is light weight but I have been informed it is strong and good quality. My bag has a front with couple of pockets on outside and on the back zip entry for the pocket and fabric pockets inside. The gusset on my mockup was two sides and the base joined in. But with the other pockets was too muck bulk on the corners and hard to lime up correctly .

So I have decided to make the gusset one whole long strip to go from one side of bag , along the base and back up the other side. I have been requested to have it as cross body long handled bag. Wondering how to ensure the connection of the handle to side of bag will be strong enough. The tape running to the base as in Havalon bag would be good but I have no seem across the base.

Should I just put the cotton inside the leather to help with strength and should I run tape along the base of bag and up the other side? Or any other suggestions would be appreciated please?

Bag size is 20 cm tall, width at base of bag is 25 cm wide and at top of bag it is 36 cm wide as the sides flair out as the set in lowered zip is not in the mock up yet. Gusset width is 8 cm wide.

The leather on my mock up is thicker but the kangaroo leather is 0.9 mm to 1 mm thick.

So my question is how best to attach cross body handle when the leather is thin Kangaroo and all in one gusset from one side underneath and up the other side?

Thank you kindly in advance,

Kind Regards Anne